OK. I'm totally lost. I have looked at this over and over. Here is what I have concluded so far,
1. This looks like a Satellite photo. If this is true, it would never fall under the category of treasure sign/symbol. Nobody 2-300 years ago would have gone to the trouble of making this as a treasure guide, because 2-300 years ago there was no such thing as manned flight(Not to mention space flight, unless, well, you know[insert Twilight Zone Theme Here]).
2. If it is a Satellite photo, it is at best an old fort or a mound of some type. Now that in itself would be a great find. If it were a mound, it should be excavated. If it is an old fort, it should be MD'd.
3. It may be a meteorite strike. Normally, they don't hit at 90 degree angles to the Earth (it would take a 90 degree hit to make this perfect circle). When they hit, they leave an oblong trench. It does happen, though. The Impact Crater in Az. is a perfect circle, but it is two miles wide and half a mile deep, and it doesn't have that neat little circle right in the middle.
4. Whatever it is I think would warrant further investigation. I would like to see ground level pictures of this. It would only take one day on site to tell if it were man made or not.
Mike